Originally, the Treaty of Rome gave the European Parliament an advisory role only.
Subsequent treaty provisions have strengthened this role culminating in the co-decision procedure established by the Treaty of Amsterdam. A legal act is made law only if the Council and Parliament agree. If disagreement exists, a conciliation committee may be convened comprised of members of the Council and Parliament with the attendance of the Commission. In certain circumstances, the Parliament may request that the Commission put forward a proposal to the Council. The Parliament may also institute proceedings against an institution for a treaty violation.
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